| 摘要 |
PURPOSE: To enable an operator to select an exchanging time even when the emptiness of a developing device is detected, and to facilitate exchanging processing in an image forming device provided with plural developing devices. CONSTITUTION: Four developing devices 31 are rotated clockwise as a whole and successively set at a developing position D. The remaining amount of developer in each developing device is detected according to the time when light emitted from a light emitting element 81 is reflected by a mirror 37 and arrives at a light receiving element 82. In the case of detecting that the developer is equal to or under a specified amount (the emptiness of the developing device), information on the developing device is stored in a memory in a control circuit and displayed on a display unit on a control panel. A key for inputting the designation of exchange is set adjacently to the display unit. By turning on the key, the developing device is moved to an exchanging position only when the information on the developing device the emptiness of which is detected is stored in the memory. |
